Conventionally, absorbent articles such as disposable diapers have been configured such that two side wall parts are provided, one on each side of a main body part, and portions of the side wall parts that serve as standing parts stand up toward the wearer by contraction of elastic yarn or the like provided on free edges of the side wall parts. When an absorbent article is worn, the pair of standing parts serves as standing gathers that come into contact with the vicinity of the top of the wearer's legs, and as a result, seepage of body waste from the absorbent article is prevented.
In the disposable diaper disclosed in Japanese Patent Application Laid-Open No. 2004-481 (Document 1), inner sheets connected consecutively to a back sheet are disposed on both right and left sides on the top sheet side. At the inner edges of the inner sheets, extendable elastic members are disposed and fixed in their extended state, forming a pair of right and left pleated gathers. Furthermore, approximately central parts of the pleated gathers in the longitudinal direction and approximately central inner parts of leg gathers in the longitudinal direction are bonded to each other. As a result, in the disposable diaper of Document 1, not only the pleated gathers but also the leg gathers take a three-dimensional form, and leakage of liquid from around the wearer's legs is effectively prevented.
Incidentally, in the absorbent article, each side wall part (standing part) stands up high from the main body part in a central part that faces the crotch area of a wearer, whereas the side wall part overlaps with the main body part in end parts that contact the skin of the wearer on the front and back sides. Meanwhile, in parts between the end parts and the central part, the side wall part generally has the same structure as in the central part, and thus when the absorbent article is worn, the standing part (standing gathers) in the boundary parts is pushed down toward the main body part, making it difficult for the upper edge (free edge) of the standing part to closely fit against the skin of the wearer, and resulting in the risk that leakage of the body waste or the like will occur.